Some applications require the machining of a hollow tubing material. In still other instances, the hollow tubing material may also be expensive or costly. For example, high cost stainless steel material that is biocompatible and will stay in the body without corroding is used in some applications. For example, small cylindrical tubes called stents may be inserted into the artery after a coronary angioplasty procedure. A stent prevents a coronary artery from closing again after a coronary angioplasty procedure. A coronary angioplasty is a medical procedure used to treat blocked coronary arteries as an alternative to a coronary bypass operation. It involves the insertion of a balloon catheter into the blocked artery and the inflation of the balloon to expand the size of the artery and relieve the blockage. A stent is placed in the coronary artery to prevent the need to repeat the angioplasty procedure. Of course, repeating the coronary angioplasty is not only unpleasant for the patient, but also places the patient at risk and is expensive. Therefore, a stent is used so as to prevent the need or lengthen the time between coronary angioplasty procedures for the patient.
Stents are made of a thin-walled metallic material and have a pattern of apertures or holes cut around the circumference of the stent, which continue along most of its length. In the coronary application, the stent reinforces the walls of the coronary artery after an angioplasty procedure. The pattern in a stent is typically cut by a laser cutting tool. The most common use of stents is in coronary arteries. However, stents are also widely used in other tubular structures, such as central and peripheral arteries and veins, bile ducts, esophagus, colon, trachea or large bronchi, and urethra. Stents are even used in the brain in some procedures. In other applications, plastic surgeons use stents for reconstructive surgery.
In manufacturing stents, basic lathe techniques have been adapted to support the tubing used to form the stent during the hole cutting process. Typically, a piece of tubing is supported between a drive mechanism and a tail stock support in the manner of a lathe. A laser cutting tool positioned above the tubing will cut the pattern by moving relative to the tubing along the length of the finished stent, the tubing being rotated as necessary to present different parts of the circumference to the laser cutting tool. After the first end and subsequent patterns are completely cut in the stent, the tubing is cut at the drive end of the stent to allow a finished stent to be completed. The completed stent is then projected toward a hard-walled catch basin by a jet of water or similar fluid. In some instances, the stent is bent or otherwise deformed as a result of hitting the catch basin.
Current manufacturing methods have other various limitations which result in a fairly high scrap rate. The current manufacturing methods also may require lengthy times for retooling or adjusting the current tooling when another type or diameter of tubing is going to be cut or formed into a finished stent. Therefore, there is a need for an apparatus and method for machining tubing that is in need of little or no adjustment and which produces less waste than current methods.